First repackage under "core".
Moved RDB, Pojo and Config stuff into "contrib" package.
No more deps from core to contrib.
Reorg utils
Added org.logic2j.core.solve.ioc.SolutionListener.Continuation
Repackaged "ioc" as "listener"
Some more code cleanup / reorg.
No public abstract on interfaces
Cleanup public members in interfaces.
Comment interfaces Prolog*